Harmonic analysis of secular changes of the orbital parameters and geomagnetic field

Avramovska, Rada and Delipetrov, Todor and Doneva, Blagica and Delipetrev, Marjan (2013) Harmonic analysis of secular changes of the orbital parameters and geomagnetic field. In: 13th International Multidisciplinary Scientific Geoconference SGEM 2013, 16-22 June 2013, Albena, Bulgaria.

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Official URL: http://sgem.org/sgemlib/spip.php?article2686&lang=...

Abstract

Paleomagnetic and paleoclimatic studies have long interconnection. Latest developments and techniques in paleomagnetnic research led to obtain more accurate data on changes in the geomagnetic field of the Earth in the geological past. According to the theory of Serbian scientist Milankovich, secular variations of the three astronomical parameters, the axial tilt, the Earth’s orbital precession and the eccentricity are the dominant factors for insolation and defining the ice ages. In the present, the value of the orbital parameters in the secular past and their values in the future are well known. Long term variations of the Earth’s orbital parameters can determine the periods of the frequencies of their changes in the geological past. There are many theories and studies from a lot of scientists where geomagnetic excursions are associated with the fall of solar radiation and ice ages. Comparing the curves of graphically displayed changes of geomagnetic excursions can be see that the peaks of the low value of the geomagnetic field is approximately between 30 and 40 000 years ago, less than a minimum period of obliquity of the axis. Resent excursions occur in roughly the same period of the reduction of the maximum value the obliquty, but do not coincide with its minimum value. Any change of the geomagnetic field appears in the phase of low or declining value of the obliquity of the axis. Dominant period of the geomagnetic excursions is from 40 to 125 000 years, which coincides with the periodicity and changes of 42,000 years of precession and 100,000 years of the eccentricity. The last maximum values of the eccentricity are associated with geomagnetic excursions. Due to the larger number of informations, We will limit to the geological past from the last reverse of geomagnetic field during the Brunhes chron [1].

Item Type: Conference or Workshop Item (Paper)
Subjects: Natural sciences > Earth and related environmental sciences
Divisions: Faculty of Natural and Technical Sciences
Depositing User: Blagica Doneva
Date Deposited: 26 Nov 2013 10:35
Last Modified: 26 Nov 2013 10:35
URI: http://eprints.ugd.edu.mk/id/eprint/8201

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